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这是一本关于verilog编程语言的教程,对学习verilog语言有帮助

<ul class="Element631">
<li class="Element601">连续复制（<span style="color: #800080">[*</span>）：连续复制说明了操作数序列的有限多的迭代匹配，它在一个匹配的结束到下一个匹配的开始之间具有一个时钟标记的延时。整个复制序列在操作数的最后一个迭代匹配的结束处匹配。</li>
<li class="Element601">跳转复制（<span style="color: #800080"> [-&gt;</span>）：跳转复制指定了操作数布尔表达式的有限多的迭代匹配，在操作数的一次匹配到后续匹配之间具有一个或多个时钟标记的延时并且之间没有操作数的严格匹配。整个复制序列在操作数的最后一次迭代匹配处匹配。</li>
<li class="Element601">非连续复制（<span style="color: #800080">[=</span>）：非连续复制制定了操作数布尔表达式的有限多的迭代匹配，它在操作数的一次匹配到后续匹配之间具有一个或多个时钟标记的延时，并且之间没有操作数的严格匹配。整个复制序列在操作数最后一次迭代匹配的时候或之后但在操作数的任何后来匹配之前匹配。</li>
</ul>&nbsp;</p>
<p class="Element10">
一个序列内的一个子序列的连续复制的效果可以通过显式地迭代子序列来获得，例如： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00594');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00594"><pre class="Element12">a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c</pre></div></div>
<p class="Element10">
&nbsp;</p>
<p class="Element10">
通过使用连续复制操作符<span style="color: #800080">[*</span><span style="color: #FF0000">3</span><span style="color: #800080">]</span>，它指示了3次迭代，这个有序的行为能够以更加简洁的方式说明： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00595');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00595"><pre class="Element12">a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b <span style="color: #800080">[*</span><span style="color: #FF0000">3</span><span style="color: #800080">]</span> <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c</pre></div></div>
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&nbsp;</p>
<p class="Element10">
一个连续复制指出操作数序列必须匹配指定数目的次数。连续复制操作符<span class="Element146"><span style="color: #800080">[*<i></span>N<span style="color: #800080"></i>]</span></span>指出操作数序列必须连续地匹配N次。例如： </p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00596"><pre class="Element12">a <span style="color: #800080">[*</span><span style="color: #FF0000">3</span><span style="color: #800080">]</span></pre></div></div>
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&nbsp;</p>
<p class="Element10">
意味着 </p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00597"><pre class="Element12">a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a</pre></div></div>
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&nbsp;</p>
<p class="Element10">
使用<span style="color: #FF0000">0</span>作为复制数目会产生一个空的序列，例如： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00598');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00598"><pre class="Element12">a <span style="color: #800080">[*</span><span style="color: #FF0000">0</span><span style="color: #800080">]</span></pre></div></div>
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&nbsp;</p>
<p class="Element10">
一个空的序列是一个不会在任何正数时钟上匹配的序列。下面的规则适用于序列与空序列串联的情况。一个空序列被表示成<i><span class="Element146">empty</span></i>，并且一个序列被表示成<i><span class="Element146">seq</span></i>。
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<li class="Element601"><span style="color: #800080">(<i><span class="Element146"></span>empty</span></i> <span style="color: #800080">##</span><span style="color: #FF0000">0</span> <i><span class="Element146">seq<span style="color: #800080"></span></i>)</span> 不会产生一个匹配</li>
<li class="Element601"><span style="color: #800080">(<i><span class="Element146"></span>seq</span></i> <span style="color: #800080">##</span><span style="color: #FF0000">0</span> <i><span class="Element146">empty<span style="color: #800080"></span></i>)</span>不会产生一个匹配</li>
<li class="Element601"><span style="color: #800080">(<i><span class="Element146"></span>empty<span style="color: #800080"></span></i> ##<i></span>n<span style="color: #800080"></i> <i></span>seq<span style="color: #800080"></i>)</span>，其中n大于0，它等价于<span style="color: #800080">(##(<i><span class="Element146"></span>n<span style="color: #800080"></span></i>-</span><span style="color: #FF0000">1</span><span style="color: #800080">) <i><span class="Element146"></span>seq<span style="color: #800080"></span></i>)</span></li>
<li class="Element601"><span style="color: #800080">(<i><span class="Element146"></span>seq</span></i> <span style="color: #800080">##<i></span>n</i> <i><span class="Element146">empty<span style="color: #800080"></span></i>)</span>，其中n大于0，它等价于<span style="color: #800080">(<i><span class="Element146"></span>seq</span></i> <span style="color: #800080">##(<i></span>n<span style="color: #800080"></i>-</span><span style="color: #FF0000">1</span><span style="color: #800080">)</span> <span style="color: #800080">'<i><span class="Element146"></span>true<span style="color: #800080"></span></i>)</span></li>
</ul>&nbsp;</p>
<p class="Element10">
例如： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00599');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00599"><pre class="Element12">b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> <span style="color: #800080">(</span>a<span style="color: #800080">[*</span><span style="color: #FF0000">0</span><span style="color: #800080">] ##</span><span style="color: #FF0000">0</span> c<span style="color: #800080">)</span></pre></div></div>
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不会产生序列的匹配。 </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00600');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00600"><pre class="Element12">b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a<span style="color: #800080">[*</span><span style="color: #FF0000">0</span><span style="color: #800080">:</span><span style="color: #FF0000">1</span><span style="color: #800080">]</span> <span style="color: #800080">##</span><span style="color: #FF0000">2</span> c</pre></div></div>
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等价于 </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00601');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00601"><pre class="Element12"><span style="color: #800080">(</span>b <span style="color: #800080">##</span><span style="color: #FF0000">2</span> c<span style="color: #800080">)</span> <span style="color: #0000FF">or</span> <span style="color: #800080">(</span>b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> c<span style="color: #800080">)</span></pre></div></div>
<p class="Element10">
语法允许在同一个序列中组合一个延时和复制。下列的例子都是被允许的： </p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00602"><pre class="Element12"><span style="color: #800080">‘</span>true <span style="color: #800080">##</span><span style="color: #FF0000">3</span> <span style="color: #800080">(</span>a <span style="color: #800080">[*</span><span style="color: #FF0000">3</span><span style="color: #800080">])</span> <span style="color: #008000">// 意味着`true ##1 `true ##1 `true ##1 a ##1 a ##1 a</span>
<span style="color: #800080">(‘</span>true <span style="color: #800080">##</span><span style="color: #FF0000">2</span> a<span style="color: #800080">) [*</span><span style="color: #FF0000">3</span><span style="color: #800080">]</span> <span style="color: #008000">// 意味着(‘true ##2 a) ##1 (‘true ##2 a) ##1</span>
<span style="color: #008000">                   // (‘true ##2 a)，进一步意味着‘true ##1 ‘true ##1</span>
<span style="color: #008000">                   // a ##1 ‘true ##1 ‘true ##1 a ##1 ‘true ##1 ‘true ##1 a</span></pre></div></div>
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&nbsp;</p>
<p class="Element10">
一个序列可以按如下方式重复： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00603');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00603"><pre class="Element12"><span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">) [*</span><span style="color: #FF0000">5</span><span style="color: #800080">]</span></pre></div></div>
<p class="Element10">
上面的例子与下面的例子相同： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00604');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00604"><pre class="Element12"><span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">)</span></pre></div></div>
<p class="Element10">
一个具有最小和最大迭代数目的重复可以使用连续重复操作符<span class="Element146"><span style="color: #800080">[* <i></span>min<span style="color: #800080"></i>:<i></span>max<span style="color: #800080"></i>]</span></span>来表达。&nbsp;</p>
<p class="Element10">
&nbsp;</p>
<p class="Element10">
例如： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00605');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00605"><pre class="Element12"><span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">)[*</span><span style="color: #FF0000">1</span><span style="color: #800080">:</span><span style="color: #FF0000">5</span><span style="color: #800080">]</span></pre></div></div>
<p class="Element10">
等价于： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00606');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00606"><pre class="Element12"><span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">)</span>
<span style="color: #0000FF">or</span> <span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">)</span>
<span style="color: #0000FF">or</span> <span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">)</span>
<span style="color: #0000FF">or</span> <span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">)</span>
<span style="color: #0000FF">or</span> <span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> a <span style="color: #800080">##</span><span style="color: #FF0000">2</span> b<span style="color: #800080">)</span></pre></div></div>
<p class="Element10">
&nbsp;</p>
<p class="Element10">
类似地： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00607');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00607"><pre class="Element12"><span style="color: #800080">(</span>a<span style="color: #800080">[*</span><span style="color: #FF0000">0</span><span style="color: #800080">:</span><span style="color: #FF0000">3</span><span style="color: #800080">] ##</span><span style="color: #FF0000">1</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span></pre></div></div>
<p class="Element10">
等价于： </p><div class="Element170">
<a href="#" onclick="CopyElementToClipboard('code00608');">Copy Code</a></div>
<div class="Element13"><div class="Element12" id="code00608"><pre class="Element12"><span style="color: #800080">(</span>b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span>
<span style="color: #0000FF">or</span> <span style="color: #800080">(</span>a <span style="color: #800080">##</span><span style="color: #FF0000">1</span> b <span style="color: #800080">##</span><span style="color: #FF0000">1</span> c<span style="color: #800080">)</span>